In general, body exudates of urine and fecal material should be received and contained by the absorbent article. However, leakage problems are common, especially leakage of exudate material which has not been absorbed by the absorbent material in the absorbent article. In general urine will be substantially all absorbed. Fecal material, by contrast, is absorbed only in part, and even the partial absorption tends to occur more slowly. This invention is directed generally toward the exudate material which has never been absorbed, as opposed to exudate material which has been absorbed into the absorbent core or other absorbent element.
Leakage generally occurs for one of two reasons. First, the exudates may be released from the user's body so rapidly that the absorption rate of the absorbent article is temporarily overpowered. In such case, the excess exudates need only be held and contained at the surface of the absorbent article for a short period of e.g. a few seconds until absorption into the absorbent article catches up with release from the body, and all readily absorbable exudate material becomes absorbed.
Second, the exudate material, especially fecal material, which is absorbed by the absorbent core more slowly than urine, may move laterally along the body-side surface of the absorbent article, to an edge of the interfacial area defined between the absorbent article and the user's body. To the extent there is an effective seal between the absorbent article and the user's body at the respective edge portion, the exudate material is retained and held between the absorbent article and the user's body pending absorption of readily absorbable portions of the exudate material. However, should there be no seal, or if the seal is ineffective or otherwise insufficient, the exudate material can move past the edge and out from between the absorbent article and the user's body. Such movement past the edge constitutes a failure of the absorbent article to perform its primary function, namely to contain the exudates.
Seal requirements for absorbent articles generally fall into three classes, namely side seals around the user's legs, front seals at the front of the user's trunk and rear seals at the rear of the user's trunk. Leg cuffs and leg flaps have been designed and implemented to prevent leakage in the sides, or leg regions, of diapers and the like. The need for front seals is somewhat limited in that the primary direction of exudate flow from the user's body is downwardly and to the rear.
The need for rear seals is significant. The problem of rear leakage is well known, especially in association with liquidous and/or explosive bowel movements, which are common in young children.
It is known to fold inwardly a flap at the rear of the absorbent article to prevent wicking of absorbed liquids to the rear edge of the absorbent article. With the in-folded rear flap, the outer cover layer generally provides a liquid barrier between the absorbent core, or the absorbent material, and the rear outer edge of the absorbent article.
The in-folded flap prevents leakage from absorbent material (in the absorbent article) to the outer edge of the absorbent article. However, it does not prevent leakage across the top surface of the in-folded flap, between the top surface of the infolded flap and the user's body.
It is also known to provide elastic properties, such as an elastic waist band, across the absorbent article at or adjacent the rear outer edge of the absorbent article. However, waist band and like elastics are not entirely effective to prevent movement of the exudate material out from between the absorbent article and the user's body. Indeed no structure has been devised in known art effective to prevent leakage of fecal material past the rear edge of diapers and like absorbent articles.
It is an object of this invention to provide an absorbent article which is effective to prevent leakage of fecal material past the rear edge of the absorbent article.
It is another object to provide an absorbent article having a rear containment reservoir for receiving and holding exudate material which has not been absorbed by the absorbent article.
It is still another object to provide a rear waist flap for disposition against the user's body, which provides an effective barrier to leakage of liquidous fecal and other material.
It is yet another object to provide elastic implementations which urge the distal edge of the rear waist flap away from the bodyside liner layer of the absorbent article and thus create an opening through which exudate material enters the rear containment reservoir.
It is a still further object to provide a spacer in the rear containment reservoir, holding open, for receiving exudates, a minimum volume of space in the rear containment reservoir.